Check the rules for your class before spending anything on this.

One innovation that saved fuel was a fan blade on the alternator. As the NASCAR car drove around the track the rushing air caused the fan blade on the alternator to spin. By not running the belt drive on the alternator it saved a bit of friction and a bit of weight due to the plastic fan being a tiny bit lighter than the fan belt.

But it was not legal under the NASCAR rules.

And while at idle the car drew on the battery. This would not be an option for street cars due to the start and stop nature of traffic.

But if you could cut the weight of a starter from your race car.......

It is worth looking into.